A multitude of security devices exists within the prior art which teach the use of supplementary devices in conjunction with a typical latching arrangement for preventing undesirable access to one's premises. Examples of such devices are supplementary chains, dead bolts and latches.
U.S. Pat. No. 4,484,463 issued on Nov. 27, 1984 by Hennessy describes a door lock guard for protecting the cylinder of a door lock upon the key cylinder side. Such door lock is permanently mounted as best illustrated in FIG. 3 by fastening elements 46. The shape of portion 18 of plate 12 formed from the appropriate materials ensures that the cylinder 34 cannot be accessed by a tool and subsequently rotated.
U.S. Pat. No. 4,074,552 describes a kit which adapts to a lock preventing tampering of the lock thus undesirable access to one's premises. Such a combination is accessible only by a special long key which will turn the cylinder of the lock.
U.S. Pat. No. 3,556,571 by Laub issued Jan. 19, 1971 describes a device for attachment to a door knob which in essence child proofs the door knob and prevents rotation of the lock bolt of a door until such time as an adult removes the attachment. The instant invention provides a number of alternative embodiments of a latch blocking element which is installed upon the interior of a door proximate the operating means of a door latch and thus prevents the rotation of the operating means in use until such time as the blocking device is repositioned. The blocking device thus prevents the rotation of the for example a key cylinder in a household door. Should the key cylinder be tampered with on the exterior of the door by an intruder, the rotation thereof would be prevented on the interior by blocking the rotation of the operating means connected to the key cylinder. Nowhere within the prior art is such a blocking means found which may be used by for example the occupant of a home as a night latch for securing his or her home.
It is therefore an object of this invention to provide a latch blocking mechanism which blocks the operation of operating means of a latching means thus preventing the rotation of the latching means from a locked to an unlocked position.
It is a further object of this invention to provide a blocking means embodied in alternative embodiments which co-operate with those latching means most broadly utilized in household latches. It is a further object of the invention to provide a latch blocking means which is easy to install, move, remove, or reposition.
Further and other objects of the invention will become apparent to a man skilled in the art when reviewing the following summary of the invention and the more detailed description of the preferred embodiments illustrated herein.